And what exactly prevents you from getting the account back with the same CD key that you will be giving to the buyer? All you have to do is contact Steam support and provide old e-mails of PoP or access to the Steam account, while claiming someone else may have your CD key. They will also ask you to provide country's ID and PayPal's Credit Card last 4 digits, which you won't be giving to the buyer. And just like that, you get your account back.
Deal with caution.